1. Field of the Invention
The present invention relates to a method for producing a pressure plate used in a hydraulic pump, and more particularly to a method for producing a pressure plate used in a hydraulic pump by connecting two plate sections together.
2. Description of the Prior Art
In a conventional hydraulic pump having a pressure plate which includes two plate sections connected together, the pressure plate is provided with a plurality of ports through some of which fluid is sucked into expanding chambers of the hydraulic pump and through the rest of which fluid is discharged from chambers which are being compressed. Such a pressure plate is shown in FIGS. 1 and 2. A conventional method for producing the pressure plate employs the following steps. At first, a plate section 1A is formed with a pair of outlet ports 2 around which annular grooves 4 are formed on a side surface 3 of the plate section 1A and another plate section 1B is formed with a pair of ports 5. Next, the another plate section 1B is properly placed on the plate section 1A, while brazing metal 6 is put in the annular grooves 4 and, then, the assembled pressure plate including the plate sections 1A and 1B is heated in a heating furnace (not shown) under pressure, so that the brazing metal 6 is melted and is forced to spread on the side surface 3 to thereby connect the plate sections 1A and 1B together. However, in the pressure plate produced in the conventional method, leakage between the plate sections 1A and 1B may be caused, since the amount of the brazing metal 6 is limited due to the small area where the groove 4 is formed and cannot be supplied on the surface 3 so much as to prevent leakage. Furthermore, the plate sections 1A and 1B may suffer from distortion due to the pressure during the heating operation.